Beyond housekeeping: snRNA diversity, regulation, and human disease

Recent analyses challenge the long-standing view of small nuclear RNAs (snRNAs) as largely uniform and functionally interchangeable molecules. Their genes undergo lineage-specific expansions and losses, and in humans, individual loci display striking sequence constraints. Recurrent germline and somatic mutations cluster within defined structural domains of both major and minor spliceosomal snRNAs, revealing that single nucleotides can be subjected to changes affecting function. Even subtle alterations within conserved base-pairing regions can reshape recognition of cis-regulatory elements, while regulated abundance and RNA modifications further tune splicing outcomes. Rather than acting solely as structural scaffolds, snRNAs function as dynamic RNA components that participate directly in spliceosome assembly and catalytic-site formation. In this review, we distill the emerging principles and consider their implications for development, tissue homeostasis, and human disease.